Mei-Chi Liu et al - Infrared Emission Spectrum of KF

8/3/2019 Mei-Chi Liu et al - Infrared Emission Spectrum of KF

1/5

OURNAL OF MOLECULAR SPECTROSCOPY 180, 188192 (1996)

RTICLE NO . 0241

Infrared Emission Spectrum of KF

Mei-Chi Liu, A. Muntianu, K.-Q. Zhang, P. Colarusso, and P. F. Bernath

Centre for Molecular Beams and Laser Chemistry, Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1

Received June 3, 1996

The high-resolution infrared emission spectrum of potassium monofluoride has been recorded with a Fourier transformspectrometer. Over 900 vibrationrotation transitions, from the 1 r 0 to the 8 r 7 vibrational bands, havebeen assigned. Improved spectroscopic constants have been obtained for the KF ground electronic state by combiningthe infrared measurements with the existing microwave data. 1996 Academic Press, Inc.

INTRODUCTION spectrometer. The technique used has been described pre-

viously in, for example, our paper on NaF ( 19 ). The KF

The KF molecule has been extensively studied by many spectrum was recorded at 900C with a resolution of 0.01ifferent spectroscopic methods. Early high resolution stud- cm01 over the range 350750 cm01 with a 3.5-mm-thick

es include molecular beam electric resonance experiments Mylar beamsplitter. The final recording consisted of 501 4 ), and millimeter-wave molecular beam spectroscopy coadded scans. A portion of the spectrum is displayed in5 ). The low resolution infrared absorption measurements Fig. 1.f KF vapor ( 6, 7) and matrix isolation spectra of the mono-

mer and dimer were published ( 8, 9 ). Improved vibrational RESULTS AND DISCUSSIONonstants were obtained in an infrared diode laser study (10)

f the 2 R 0, 3 R 1 and 4 R 2 overtones. By combining Although potassium has three natural isotopes, 39Ksmall number of infrared measurements with the existing (93.26%), 40K (0.01%), and 41K (6.73%), only the main

microwave data, Maki and Lovas ( 10 ) obtained a reliable set isotope was observed in this experiment. Over 900 transi-f Dunham constants. Recent experimental measurements on tions were observed and analyzed. The assignment of the

KF include a measurement of the spontaneous vibrational rotational lines was based on the previous constants found

ecay rates ( 11), electron diffraction ( 12 ), and a more ex- in the literature (10). The position of the lines was calibratedensive measurement of the hyperfine structure ( 13 ). in accordance with the strong pure rotational HF lines ( 21,

The KF molecule has also been the target of several ab 22) that appeared in the spectrum. Eight vibrational bandsnitio calculations of molecular properties such as the disso-

iation energy ( 14). More recently, Modisette et al. (15 ),

eported a calculation of the electronic structure using the

ncreasingly popular density functional approach, while Gar-

iaCuesta et al. (16) used large basis sets and extensive

lectron correlation. Dyall and Partridge (17) explored the

ffects of relativistic corrections to the properties of alkali

uorides.

In the work reported here we have made the first highesolution measurements of the fundamental ( 1 r 0)

ibrationrotation band and related hot bands by infrared

mission spectroscopy with a Fourier transform spectrome-

er. High resolution Fourier transform data are now available

or the entire nonradioactive alkali fluoride family, LiF (18 ),

NaF (19), KF (this work), RbF (20), and CsF (20 ).

EXPERIMENTAL DETAILS

The high resolution infrared emission spectrum of KF has FIG. 1. A portion of the R branch of the vibrationrotation spectrumof KF. The lines of the 10 band are marked with their J values.een recorded with a Bruker IFS 120 HR Fourier transform

18822-2852/96 $18.00

opyright 1996 by Academic Press, Inc.

ll rights of reproduction in any form reserved.


2/5

INFRARED EMISSION OF KF 189

TABLE 1

Observed Rovibrational Line Positions of the X 1S/ State of KF in cm01 (ObservedCalculated Values in Units of 1003 cm01 Are

Shown in the Column Labeled D)

Copyright 1996 by Academic Press, Inc.


3/5

LIU ET AL.90

TABLE 1Continued



4/5

INFRARED EMISSION OF KF 191

TABLE 1Continued

TABLE 3

Spectroscopic Constants for the X 1S/

Ground State of KF (in cm01)TABLE 2

Dunham Yij Coefficients for the X1S/ Ground State of KF



5/5

LIU ET AL.92

3. R. van Wachem, F. H. de Leeuw, and A. Dymanus, J. Chem. Phys.rom 1 r 0 to 8 r 7 were observed; the line47, 2256 (1967).ositions are reported in Table 1. In order to obtain improved

4. H. Dijkerman, W. Flegel, G. Graff, and B. Monter, Z. Naturforsch. Apectroscopic constants for KF that can describe both the

27, 100 (1972).nfrared and microwave data, all of the lines reported in 5. S. E. Veazey and W. Gordy, Phys. Rev. 138, 1303 (1965).

6. V. I. Baikov and K. P. Vasilevskii, Opt. Spectrosk. 22, 198 (1967).Table 1 were fitted, together with the hyperfine-corrected7. R. K. Ritchie and H. Lew, Can. J. Phys. 42, 43 (1964).microwave (1, 4) and millimeter-wave transitions ( 5) be-8. H. Schaber and T. P. Martin, J. Chem. Phys. 70, 2029 (1979).onging to the first three vibrational levels. Dunham Yij coef-9. Z. K. Ismail, R. H. Hauge, and J. L. Margrave, J. Inorg. Nucl. Chem.,

icients, listed in Table 2, were obtained by fitting the data35, 3201 (1973).

et to the energy level expression ( 23 ) 10. A. G. Maki and F. J. Lovas, J. Mol. Spectrosc. 95, 80 (1982) .11. D. R. Bedding and T. I. Moran, J. Chem. Phys. 84, 3598 (1986).

12. J. G. Hartley and M. Fink, J. Chem. Phys. 89, 6058 (1988).E(, J)

i ,j

Yij / 12

i

[J(J/ 1)] j . 13. G. Paquette, A. Kotz, J. Cederberg, D. Nitz, A. Kolan, D. Olson, KGunderson, S. Lindaas, and S. Wick, J. Mol. Struct. 190, 143 (1988)

14. S. R. Langhoff, C. W. Bauschlicher, Jr., and H. Partridge, J. Chem.

Phys. 84, 1687 (1986).The customary spectroscopic constants for the X1S/ ground 15. J. Modisette, L. Lou, and P. Nordlander, J. Chem. Phys. 101, 8903

tate of KF are given in Table 3. From the Y01 equilibrium (1994).16. I. Garcia-Cuesta, L. Serrano-Andres, A. Sanchez de Meras, and Ionstant, the equilibrium internuclear separation re

Nebot-Gil, Chem. Phys. Lett. 199, 535 (1992)..1714558(2) A was calculated.17. K. G. Dyall and H. Partridge, Chem. Phys. Lett. 206, 565 (1993).

18. H. G. Hedderich, C. I. Frum, R. Engleman, and P. F. Bernath, Can. J.ACKNOWLEDGMENT Chem. 69, 1659 (1991).

19. A. Muntianu, B. Guo, and P. F. Bernath, J. Mol. Spectrosc. 176, 274We thank the Natural Sciences and Engineering Research Council of (1996).

anada for support. 20. A. G. Maki and W. B. Olson, J. Mol. Spectrosc. 140, 185 (1990).

21. R. B. Le Blanc, J. B. White, and P. F. Bernath, J. Mol. Spectrosc. 164,

574 (1994).REFERENCES22. R. S. Ram, Z. Morbi, B. Guo, K.-Q. Zhang, P. F. Bernath, J. Vander

Auwera, J. W. C. Johns, and S. P. Davis, Astrophys. 103, 247 (1996)1. G. W. Green and H. Lew, Can. J. Phys. 38, 482 (1960).

23. J. L. Dunham, Phys. Rev. 41, 721 (1932).2. R. van Wachem and A. Dymanus, J. Chem. Phys. 46, 3749 (1967).


Documents

Mei-Chi Liu et al - Infrared Emission Spectrum of KF